To crossfeed or not to crossfeed? That is the question...

Dec 2, 2017 at 3:49 PM Post #241 of 2,192
here is what I use in so called "true stereo" for the convolution. well I flatten the low end(because I like it like that and it doesn't really impact localization), and apply EQ for whatever headphone/IEM I use, but else that's it. based on 30° impulse of some HRTF I found online that worked best for my head. the subject had a massive difference between left and right in some part of the response that I could totally notice, so I just bounced the left ear values for both ears(well reversed).

the end result is no realiser A16, but it's by far the best Xfeed I've had and I've tested MANY. customization is unavoidable to get better results. at least it is for poor me with my non average head.
What is the frequency resolution/FFT size? Window-function? Below 200 Hz it seems junk due to resolution limit/windowing
 
Dec 2, 2017 at 4:35 PM Post #242 of 2,192
Except...you've ignored how recordings are made and mixed. A hard-panned, acoustically or electronically "dry" sound is indeed very rare, sort of an "effect" rather than a normal mix technique. As soon as you put ambience around the sound and in the opposite channel that close perspective is mitigated.

[4] Wasn't rare at all in 1958! Even the newest compressed "headphone-friendly" pop has ILD > 3 dB bass.

[5] You are clearly a person, who knows a lot and has done a lot for decades, but for some reason you have these strange fights against me. The science is behind me. Larger ILD means the sound source is close to the other ear. It's not only self-evident, but measured HRTFs show it clearly. I really don't know what's wrong with you. :rolling_eyes:

Crossfeeders don't serve coffee. They don't fix everything in the sound. They fix things related to excessive stereo separation and that's it. Why do I even need to say this?

I don’t think he is trying to fight.

I believe he is trying to figure out what is in your opinion the percentage of recordings with unnatural ILD.

So please, do you mind to describe which recordings from 1958 are you referring to and how they were mixed?

To have a numerical perspective, just forget the algorithms that choose music according to music preference and past choices and tell us: if anybody plays 100 musics choosen randomly, how many does have in your opinion unnatural ILD?

You write about crossfeed as if they (recordings with unnatural ILD) were the majority.

To put into perspective, this is Professor Choueiri opinion, which seems to be the opposite, in other words, the minority of recordings:

13 Is the 3D realism of BACCH™ 3D Sound the same with all types of stereo recordings?

The stereophonic recording technique that is most accurate at spatially representing an acoustic sound field is, incontestably, the so-called “binaural” recording method15, which uses a dummy head with high-quality microphone in its ear 16. Until the recent advent of BACCH™ 3D Sound, the only way for an audiophile to experience the spectacular 3D realism of binaural audio was through headphones. Many such recordings exist commercially, and more have recently been made thanks to the iPod revolution.

BACCH™ 3D Sound shines at reproducing binaural recordings through two loudspeakers and gives an uncannily accurate 3D reproduction that is far more stable and realistic than that obtained by playing binaural recordings through headphones17.

All other stereophonic recordings fall on a spectrum ranging from recordings that highly preserve natural ILD and ITD cues (these include most well-made recordings of “acoustic music” such as most classical and jazz music recordings) to recordings that contain artificially constructed sounds with extreme and unnatural ILD and ITD cues (such as the pan-potted sounds on recordings from the early days of stereo). For stereo recordings that are at or near the first end of this spectrum, BACCH™ 3D Sound offers the same uncanny 3D realism as for binaural recordings18. At the other end of the spectrum, the sound image would be an artificial one and the presence of extreme ILD and ITD values would, not surprisingly, lead to often spectacular sound images perceived to be located in extreme right or left stage, very near the ears of the listener or even sometimes inside of his head (whereas with standard stereo the same extreme recording would yield a mostly flat image restricted to a portion of the vertical plane between the two loudspeakers).

Many of well-made popular music recordings over the past two decades have been recorded and mastered by engineers who understand natural sound localization and construct mostly natural-like stereo images, albeit artificially, using realistic ILD and ITD values. Such recordings would give a rich and highly enjoyable 3D soundstage when reproduced through BACCH™ 3D Sound.

——————
15 The accuracy is due to the fact that binaural audio preserves not only the correct ILD and ITD cues discussed in Q&A10, but also contains so-called “spectral cues,” which are the effects the torso, head and ears have on the frequency response and which the brain uses, in addition to ILD and ITD cues, to locate sound, especially at higher frequencies.

16 The spatial accuracy of dummy head recording is only surpassed by recordings made with microphones placed in the listener’s own ears - alas, a rare commodity that would have benefits upon playback for only that listener.

17 This is because binaural playback through headphones or earphones is very prone to head internalization of sound (which means that the sound is perceived to be inside the head) and requires, in order to avoid this problem, an excellent match between the geometric features of the head of the listener and those of the dummy head with which the recording wasmade (this problem has been recently surmounted by the Smyth headphones technology http://www.smyth-research.com/). Pure Stereo does not suffer from this problem as the sound isplayed back though loudspeakers far from the listener’s ears.

18 The 3D realism is the same although the ability of reproducing a sound source at a location that accurately corresponds to the original location is relatively decreased due to the absence of spectral cues.
 
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Dec 2, 2017 at 5:18 PM Post #243 of 2,192
I believe he is trying to figure out what is in your opinion the percentage of recordings with unnatural ILD.

He should know that by now. I have given the "magic" number 98 %.

So please, do you mind to describe which recordings from 1958 are you referring to and how they were mixed?

A lot of recordings of that era were recorded hard panned so that "half" of the instruments were on the left and "half" on the right and perhaps some in the middle. Example: Dave Brubeck: Jazz Impressions of Eurasia.



To have a numerical perspective, just forget the algorithms that choose music according to music preference and past choices and tell us: if anybody plays 100 musics choosen randomly, how many does have in your opinion unnatural ILD?[/UOTE]

98

You write about crossfeed as if they (recordings with unnatural ILD) were the majority.

Yes, because that's my overhelming experience. I crossfeed almost everything and in rare cases I find out that something sounds good/better without crossfeed. Example of a recordings with natural ILD which I listen to without crossfeed:

Johann Christoph Graupner: Partitas for harpsichord, Naoko Akutagawa, Naxos
 
Dec 2, 2017 at 5:30 PM Post #244 of 2,192
He should know that by now. I have given the "magic" number 98 %.

Then pinnahertz and Professor Choueiri are in disagreement with you. :grin:

A lot of recordings of that era were recorded hard panned so that "half" of the instruments were on the left and "half" on the right and perhaps some in the middle. Example: Dave Brubeck: Jazz Impressions of Eurasia.



Anyway, thank you very much for that recording! Very cool! :thumbsup:
 
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Dec 2, 2017 at 5:42 PM Post #245 of 2,192
Since subwoofers typically output only lowest bass, only in larger rooms we have problems with modes and small room behaves more like a pressure chamber and it's easier to find a good placement for the sub. In larger rooms more subs helps in having more flat response and od course more SPL to fill the room.

My room has a bar straight back off the end of it and a bathroom at a right angle to that. It's shaped sort of like an exponential horn. I find that there is a huge bass peak in the shower stall! The arrangement of the furniture in the room, the construction of the walls / position of the bookcases, and the high peaked ceiling seems to discourage primary reflections. Most of the reflections came off the concrete slab floor, but a thick oriental rug took care of that problem.
 
Dec 2, 2017 at 7:13 PM Post #246 of 2,192
Then pinnahertz and Professor Choueiri are in disagreement with you. :grin:
Mr. pinnaherz maybe. Don't know about Professor Choueiri, who is talking about speaker audio and how to get "headphone binaural" sound with speakers using "anti-crossfeed", crosstalk canceling. That's completely different from what I'm talking about.

Nearly all recordings are produced for speakers, so it's no wonder they work just fine with speakers, but when you listen to them with headphones, without the support of acoustic crossfeed or other crossfeed the ILD/ITD problems show themselves.

Anyway, thank you very much for that recording! Very cool! :thumbsup:

I'm glad you like. Cool recording indeed. :sunglasses:
 
Dec 2, 2017 at 7:33 PM Post #247 of 2,192
Has there ever been an experiment done where a binaural recording was compared with a normal mic-ed/speaker-ed mix of the same material recorded on the same dummy head? Would seem like something useful for quantifying the ILD/ITD/spectral errors, at least for the head facing straight forward.
 
Dec 2, 2017 at 8:05 PM Post #248 of 2,192
Has there ever been an experiment done where a binaural recording was compared with a normal mic-ed/speaker-ed mix of the same material recorded on the same dummy head? Would seem like something useful for quantifying the ILD/ITD/spectral errors, at least for the head facing straight forward.

Very interesting question!

Do you mean:

1. 5 speakers in a row of 2 meters parallel to the coronal plane of the dummy head.
2. Five sweeps/chirps from 20hz to 20khz are played one after another in each speaker and recorded by the dummy head (binaural master reference audio file).
3. Five sweeps/chirps from 20hz to 20khz are played one after another in each speaker and recorded by the an ORTF microphone pattern (ORTF master reference audio file).
4. The two farther speakers in the same row of 2 meters parallel to the coronal plane of the dummy head now play the “binaural master reference audio file” and is against recorded by the dummy head (playback acoustic crosstalk corrupted audio file A).
5. The two farther speakers in the same row of 2 meters parallel to the coronal plane of the dummy head now play the “ORTF reference audio file” and is against recorded by the dummy head (playback acoustic crosstalk corrupted audio file B).
6. Compare playback acoustic crosstalk corrupted audio files A and B?

Dr. Choueiri might have done it, but I never saw any paper about such experiment. Theoretically they already know the ILD/ITD/spectral cues from the dummy head itself (the HRTF is certainly in the research database of HRTF) and recording engineers also know ILD/ITD from an ORTF pattern (might be useful to place a foam disc between the mics).

I just can’t find graphics in the internet to compare such chains/paths.
 
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Dec 2, 2017 at 8:51 PM Post #249 of 2,192
[1] Spatial deafness is simply a subgenre of Auditory Adaptation.
Please cite a reference (other than your own).
[2] I really don't get this. To me recordings that work best without crossfeed are few and far between.
You are one opinion, and you have never once referenced anything that shows your opinion is widely held, or even held by anyone but you. If crossfeed were so good, so essential, such a key function, then why hasn't it been standard on even 1% of all music players since the original Sony Soundabout (Walkman) of 1979? It certainly could have been done and very low cost. But it wasn't, hasn't, and isn't still. "Loudness Compensation" had a far better market penetration, and that didn't work well either!
[3] I don't underestimate room modes! I have done research work how to pre-filter signal before it's fed to the speakers to reduce room modes. In pathological cases I suppose it's possible to have ILD bigger than 3 dB, at a certain frequency and place in the room and at reduced SPL level masked by other frequencies.
You can't reduce room modes with pre-filter, and I'm sure you know that. You can only reduce the results of room modes. Room modes can only be reduced with physical means.
[4] Wasn't rare at all in 1958! Even the newest compressed "headphone-friendly" pop has ILD > 3 dB bass.
And exactly how many stereo recordings were released in 1958? What percentage of the total releases ever does that make up? Wouldn't be reasonable to expect early stereo mixes to have a few issues until we learned how to handle the new medium? You've "cherry-picked" an example, which is thus meaningless.

[5] You are clearly a person, who knows a lot and has done a lot for decades, but for some reason you have these strange fights against me. The science is behind me.
We have these "strange fights" because your science doesn't apply to reality, it's specifically targeting contrived conditions.

However, my objects are, and have been:

1. Promoting headphone cross-feed as if it were a "compensation" for some form of distortion, and as if it were a universal solution. Such is not the case. The application of cross-feed is highly generalized at best, inappropriate at least, and never compensates properly for any speaker-mix condition because you have no idea what the intentions were in the first place, nor the precise monitoring conditions used in the mix. You advance it as if it were a complimentary equalizer (like RIAA) when it is at very best a coarse approximation based on uneducated assumptions.

2. You authenticate your "science" with your own passionate opinion, but offer no other statistical listener preference for crossfeed.

3. Your opinions are (still!) stated as immutable fact. And when others express their opinions you view them as personal attacks.

4. Your "science" is tightly targeted at a narrow set of conditions, and ignores the facts that actual mixes are as much art as science. There's no "correcting" for "art".
Larger ILD means the sound source is close to the other ear. It's not only self-evident, but measured HRTFs show it clearly. I really don't know what's wrong with you. :rolling_eyes:
No it does not. ILD is not the sole proximity cue! Your HRTF model may work in an anechoic space, but doesn't account for a real room of any size or reflective nature. In other words, your HRTF alone doesn't model spatial hearing in real life.
[6]
1. Yes. However, a few decibels of ILD sounds more lively imo so I don't always go for mono bass.
Everyone please note the emphasized text. It is exactly what it says: opinion. That means there will be other conflicting opinions! You want fact? Collect statistics, don't quote your own opinion! The bulk of modern music producers and engineers disagree with you.
2. Room modes create typically 10-15 dB peaks and even deeper dimples. However, most of the time this doesn't affect much ILD and if it does, at low level, masked and possibly below the hearing threshold anyway. Usually the modes become dense enough to transform into reverberation below 200 Hz where the wavelength is about 2 m. You are splitting hairs.
No, not splitting hairs at all. In fact, you are correct that modes create 10-15dB peaks, and dips as deep as 30dB or more. You are incorrect in that reverberation below 200Hz causes modes to become denser. Simply not true, and if you'd measure a few small rooms, you'd know that. Those deep dips are not correctable because room EQ systems must limit gain to only a few dB (Audyssey's gain limit is 9dB, for example) because of what that kind of gain does to amplifier power requirements and speaker power handling. If you'd bother to do a few real-room measurements you'd see radical dips that are very, very location specific. In fact, that's why room EQ can only be properly done by averaging many measurement points. However, ears sit in single positions, and therefore are subject to some rather deep frequency specific notches.
Yes, what I said doesn't work in every possible pathological situation, but in general it does and those pathological situations are called "very bad acoustics." People tend to fix them, at least those who care about fidelity. Often all it takes is to move your speakers or chair a feet to make a diffence.
You really should get out and measure like two dozen rooms and see what reality is like. No, those are not pathological situations, they are typical of single-sub rooms. Yes, we do try to fix them with treatment and multiple subs, but if you're working with two-speaker stereo, you cannot move your chair much! Sub-200Hz dips occupy real estate, and your chair can only be moved along the center-line. If you move a speaker, you'll also move the center line, but you can't move a speaker enough to mitigate room mode dips at the optimum LP! Sorry, expericence shows the grim reality. And that's just another reason why multiple-sub, multichannel audio wins hands down.
3. Yes, when we talk about the quality of bass. I was talking about ILD only. The quality aspect does indeed support monophonic or near-monophonic bass. Reducing the ILD at bass in a recording say from 10 dB to 3 dB is a big step toward that.
But most bass is mixed 0dB channel difference (center), and with good reason. There is absolutely no performance or perspective advantage to mixing bass 3dB off center in stereo.
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Crossfeeders don't serve coffee. They don't fix everything in the sound. They fix things related to excessive stereo separation and that's it. Why do I even need to say this?
Cross-feed changes stereo separation, that's it. Whether or not that's an improvement (a "fix") is entirely subjective, and varies with every recording from improvement all the way to detriment.

You have presented no data to support the premise that cross-feed is either universally desired, or perceived as an improvement at all, much less that it is over the (claimed) majority of recordings. None. Only one person (your) opinion.

Why do I need to say that?
 
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Dec 2, 2017 at 8:59 PM Post #250 of 2,192
Has there ever been an experiment done where a binaural recording was compared with a normal mic-ed/speaker-ed mix of the same material recorded on the same dummy head? Would seem like something useful for quantifying the ILD/ITD/spectral errors, at least for the head facing straight forward.
Sure, there are a hadfull of recordings made simultaneously using both methods, but hard to compare since binaural fails on speakers.
 
Dec 2, 2017 at 9:00 PM Post #251 of 2,192
Since subwoofers typically output only lowest bass, only in larger rooms we have problems with modes and small room behaves more like a pressure chamber and it's easier to find a good placement for the sub. In larger rooms more subs helps in having more flat response and od course more SPL to fill the room.
Define larger vs smaller.
 
Dec 2, 2017 at 9:32 PM Post #252 of 2,192
Sure, there are a hadfull of recordings made simultaneously using both methods, but hard to compare since binaural fails on speakers.

Yes, that would imply a subjective assessment of both the musical recording and the subsequent filtering in each path.

Now I am curious to know what filter Chesky Records uses to make their binaural recordings compatible with regular speakers playback (with acoustic crosstalk).

It cannot be an inverse HRTF otherwise it would ruin the 3d effect with crosstalk cancellation. Maybe some spectral smoothing since elevation is not critical?

I am sure that Professor Choureiri suggest applying his Bacch filter within the master, but then your listener still need to stay still:

20 Can BACCH™ 3D Sound be experienced without the the BACCH™ 3D Sound Processor?
Yes. If a stereo signal is filtered through a BACCH™ 3D Sound processor and recorded it becomes a BACCH™ 3D Sound recording and does not require playback through a BACCH™ 3D Sound Processor. It can then be played back on any normal stereo system and can be heard in 3D with no special hardware or processing. (Such pre-processed BACCH™ 3D Sound recordings are generally made with non-customized (universal) u-BACCH filters in order to make them compatible with all stereo playback systems.)

This feature is piquing the interest of a number of leading recording and mixing engineers, and recording labels, who are interested in making new audio recordings in 3D or reissuing existing stereo recordings in 3D. The consumer can play these recordings in 3D on a regular stereo system without any specialized equipment.

For the audiophile, however, the customized BACCH™ 3D Sound processor would remain indispensable as it 1) allows real-time processing of existing stereo recordings and 2) offers levels of spatial and tonal fidelity that are only possible with customized/individualized filters
 
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Dec 2, 2017 at 9:35 PM Post #253 of 2,192
He should know that by now. I have given the "magic" number 98 %.
I do know that, but you've never backed that number up with data. It's just your opinion, that's a statistic of 1. Do you realize what the margin of error on that is?
A lot of recordings of that era were recorded hard panned so that "half" of the instruments were on the left and "half" on the right and perhaps some in the middle. Example: Dave Brubeck: Jazz Impressions of Eurasia.
That's not a "lot", that's One. How many stereo recordings were released in 1958? What percentage of the total of all stereo recordings is that?
 
Dec 2, 2017 at 9:58 PM Post #254 of 2,192
Yes, that would imply a subjective assessment of both the musical recording and the subsequent filtering in each path.

Now I am curious to know what filter Chesky Records uses to make their binaural recordings compatible with regular speakers playback (with acoustic crosstalk).

It cannot be an inverse HRTF otherwise it would ruin the 3d effect with crosstalk cancellation. Maybe some spectral smoothing since elevation is not critical?

I am sure that Professor Choureiri suggest applying his Bacch filter within the master, but then your listener still need to stay still:
Did you read this?
 
Dec 2, 2017 at 10:09 PM Post #255 of 2,192
Did you read this?

Thank you very much as usual, @pinnahertz!

Some previous reporting has seemed to indicate the "+" is related to filters developed by Professor Edgar Choueiri of the 3-D Audio and Applied Acoustics (3D3A) Laboratory at Princeton University.
This is not the case. The "+" indicates that the EQ changes due to the pinna effects on the tonal character imparted on the sound has been restored to neutral EQ using carefully chosen compensation curves.
Read more at https://www.innerfidelity.com/conte...dphone-demonstration-disc#IzEmD8iz8lEHGfSo.99
 
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